Análise da suscetibilidade e vulnerabilidade aos processos erosivos da Bacia Hidrográfica do Rio São Francisco no estado de Sergipe

Abstract

Human interventions in the São Francisco River Basin in Sergipe State, the area of study of this work, accelerate the erosive processes on the ground and siltation in the body of water. Given this, this work aimed to delimit the susceptible and vulnerable areas to erosive processes through geoprocessing techniques. For this, SRTM data, thematic maps provided by CPRM, SEMARH, and the QGIS software were used. Initially, maps of slope, hypsometry, erosivity, erodibility were made, giving weights to their respective thematic classes in relation to the predominance of pedogenesis and morphogenesis processes. Then, the Hierarchical Analysis Process (AHP) method was applied to determine the relative importance among the natural factors controlling erosive processes. Through Map Algebra the erosion susceptibility map was obtained by integrating the slope, hypsometry, erodibility and erosivity maps. The erosion vulnerability map resulted from the integration of the previous product with the land cover. From the analysis of the results it was identified that the São Francisco River Basin presents predominantly low potential to erosive susceptibility, about 65% of the total area. Regarding the vulnerability of the study area, it was found the predominance of regions with low erosive potential, due to pasture areas. The applied methodology proved to be efficient, robust and suitable for analysis of erosive processes. Thus, the products generated are technical and managerial tools to assist in the decision making necessary to minimize the social and environmental impacts resulting from erosion. In this sense, it is suggested the discipline of surface and subsurface waters and the containment of the slopes, measures established in the scientific literature to avoid, minimize, recover and manage erosive processes in urban and / or rural areas.